#include <iostream>
using namespace std;

int main()
{
	int k, a, b, v;
	cin>>k>>a>>b>>v;

	/*int sectionsNeeded = a/v + (a%v ? 1 : 0);
	int barsNeeded = sectionsNeeded - 1;
	if (b < barsNeeded)
	{
		// not enough bars
		int extraBoxes = barsNeeded - b;
		cout<<b/k + ((b%k)?1:0) + extraBoxes<<endl;
	}
	else
	{
		if (sectionsNeeded > 1)
			cout<<sectionsNeeded/k + ((sectionsNeeded%k)?1:0)<<endl;
		else
			cout<<1<<endl;
	}*/

	int totalNuts = 0;
	int boxes = 0;
	int bars = 0;
	while (bars+k-1 <= b)
	{
		bars += k-1;
		boxes++;
		totalNuts += k*v;

		if (totalNuts >= a) break;
	}

	int left = (b-bars+1)*v;
	if (totalNuts < a)
	{
		if (totalNuts+left >= a)
		{
			boxes += 1;
			cout<<boxes<<endl;
			return 0;
		}

		totalNuts += left;
		boxes++;
		while (totalNuts < a)
		{
			totalNuts += v;
			boxes++;
		}
	}
	
	cout<<boxes<<endl;
}